In the past, cam locks have been installed in file cabinets and other metal cabinets in one of two ways. The first would be to insert the lock through a hole in the front of the panel, and then reach behind and slip a fork clip into fork clip slots in the lock to hold it in place. If the lock was single cam, the cam could be pre-installed and also slipped through the hole. If double cam (two cams at 90 degrees from one another), such could not fit through the panel opening and would have to be attached from the rear with a Keps nut (combined nut and lockwasher) or a Sems screw. This system required considerable work behind the panel, was expensive, and often resulted in cut fingers, in addition to low employee morale.
An improvement on this system was developed about twenty years ago, and eliminated the use of fork clips. A spring retaining clip had a split circular band at its inner end and two spring ears flaring outwardly towards the panel. The band fit into a peripheral channel formed about the lock cylinder near its inner end. When the cam lock was inserted through the hole, the ears were pressed inwardly to fit within the hole, and, after the lock was fully in position, they snapped out, pressing against the inner surface of the panel to hold the lock in place. This represented an improvement and, with single cam locks, allowed full installation from the front. With double cam locks, the cam still had to be installed from the back as before.
This improvement had drawbacks, however. The band had to be opened up to be assembled in the channel. Sometimes it didn't completely close and thus did not fit tightly around the body of the lock. Sometimes, it would hook when the lock was inserted through the panel. Further, it required a longer lock body to provide space for the channel, adding cost and making it unusable in shallow places.